1/*
2 * libjingle
3 * Copyright 2012 Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 *  1. Redistributions of source code must retain the above copyright notice,
9 *     this list of conditions and the following disclaimer.
10 *  2. Redistributions in binary form must reproduce the above copyright notice,
11 *     this list of conditions and the following disclaimer in the documentation
12 *     and/or other materials provided with the distribution.
13 *  3. The name of the author may not be used to endorse or promote products
14 *     derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28// The CaptureManager class manages VideoCapturers to make it possible to share
29// the same VideoCapturers across multiple instances. E.g. if two instances of
30// some class want to listen to same VideoCapturer they can't individually stop
31// and start capturing as doing so will affect the other instance.
32// The class employs reference counting on starting and stopping of capturing of
33// frames such that if anyone is still listening it will not be stopped. The
34// class also provides APIs for attaching VideoRenderers to a specific capturer
35// such that the VideoRenderers are fed frames directly from the capturer.
36// CaptureManager is Thread-unsafe. This means that none of its APIs may be
37// called concurrently. Note that callbacks are called by the VideoCapturer's
38// thread which is normally a separate unmarshalled thread and thus normally
39// require lock protection.
40
41#ifndef TALK_MEDIA_BASE_CAPTUREMANAGER_H_
42#define TALK_MEDIA_BASE_CAPTUREMANAGER_H_
43
44#include <map>
45#include <vector>
46
47#include "talk/media/base/capturerenderadapter.h"
48#include "talk/media/base/videocommon.h"
49#include "webrtc/base/sigslotrepeater.h"
50#include "webrtc/base/thread_checker.h"
51
52namespace cricket {
53
54class VideoCapturer;
55class VideoRenderer;
56class VideoCapturerState;
57
58class CaptureManager : public sigslot::has_slots<> {
59 public:
60  enum RestartOptions {
61    kRequestRestart,
62    kForceRestart
63  };
64
65  CaptureManager();
66  virtual ~CaptureManager();
67
68  virtual bool StartVideoCapture(VideoCapturer* video_capturer,
69                                 const VideoFormat& desired_format);
70  virtual bool StopVideoCapture(VideoCapturer* video_capturer,
71                                const VideoFormat& format);
72
73  // Possibly restarts the capturer. If |options| is set to kRequestRestart,
74  // the CaptureManager chooses whether this request can be handled with the
75  // current state or if a restart is actually needed. If |options| is set to
76  // kForceRestart, the capturer is restarted.
77  virtual bool RestartVideoCapture(VideoCapturer* video_capturer,
78                                   const VideoFormat& previous_format,
79                                   const VideoFormat& desired_format,
80                                   RestartOptions options);
81
82  virtual bool AddVideoRenderer(VideoCapturer* video_capturer,
83                                VideoRenderer* video_renderer);
84  virtual bool RemoveVideoRenderer(VideoCapturer* video_capturer,
85                                   VideoRenderer* video_renderer);
86
87  sigslot::repeater2<VideoCapturer*, CaptureState> SignalCapturerStateChange;
88
89 private:
90  typedef std::map<VideoCapturer*, VideoCapturerState*> CaptureStates;
91
92  bool IsCapturerRegistered(VideoCapturer* video_capturer) const;
93  bool RegisterVideoCapturer(VideoCapturer* video_capturer);
94  void UnregisterVideoCapturer(VideoCapturerState* capture_state);
95
96  bool StartWithBestCaptureFormat(VideoCapturerState* capture_info,
97                                  VideoCapturer* video_capturer);
98
99  VideoCapturerState* GetCaptureState(VideoCapturer* video_capturer) const;
100  CaptureRenderAdapter* GetAdapter(VideoCapturer* video_capturer) const;
101
102  rtc::ThreadChecker thread_checker_;
103  CaptureStates capture_states_;
104};
105
106}  // namespace cricket
107
108#endif  // TALK_MEDIA_BASE_CAPTUREMANAGER_H_
109